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What is cold water shock? Experts warn of risk and how to stay safe

On a hot day, your first instinct to cool down might be to jump into the nearest body of cold water. That could be a dangerous mistake.
/ Source: TODAY

Over the July Fourth holiday, many families in the U.S. head to lakes, oceans or rivers to escape the heat and relax. Though, it's important to remember that the water in most areas is still very cold this time of year — and could be deadly.

In May 2017, 4-year-old girl London DeDios fell into the Provo River in Utah. According to the Utah County Sheriff's Office, quickly afterward, her mother, Brenda Nalleli DeDios, 34, and a bystander, Sean Zacharey Thayne, 30, both jumped in after her.

DeDios and Thayne couldn't locate the girl, and they were not able to get out of the river themselves. After authorities rescued them, they were transported to Utah Valley Hospital and pronounced dead. The 4-year-old girl's body was recovered the next day.

London DeDios and Brenda Nalleli DeDios
4-year-old London kisses her mom, Brenda, in a family photo.Go Fund Me

Though the river is dangerous on its own, full of rocks and branches, the temperature of the rapid water may have played a role.

"This river is cold in August when it's boiling outside," Utah County Sheriff's Sergeant Spencer Cannon told The Salt Lake Tribune. "It's even colder now, with snow melt coming off the mountains."

Daryl Devey, operations and maintenance manager at the Central Utah Water Conservancy, said that the water that day was around 47-50 degrees in that area of the river.

"That is really cold," noted Paul Newman, a recreational boating safety specialist for the U.S. Coast Guard. "Nothing compares you for that cold ... The 4-year-old was probably completely panicked," he added, though he is not involved with the case.

Cold water shock is rare, but more likely in warmer months when people are hot and don't consider water temperatures. In July 2015, Cameron Gosling, a 14-year-old boy, jumped into the River Wear, just outside of Durham, England, and never resurfaced. His drowning was caused by cold water shock.

Now his mother, Fiona Gosling, works with the local county government to warn people of the dangers of cold bodies of water.

Cameron Gosling
Cameron Gosling jumped into the river on a hot summer day, and never resurfaced.Courtesy of Fiona Gosling

“Until we had to live with losing Cam, we had never heard of cold water shock,” Gosling told TODAY, via email. “It’s a subject that’s not spoken about enough.”

In the U.S., there's an average of more than 3,500 unintentional drowning deaths each year, according to the Centers for Disease Control and Prevention. Newman believes a number of unexplained natural water drownings in the U.S. could be linked to the condition. He's seen enough of them over the course of his 10-year career with the Coast Guard to speak out about the risk.

Cold water shock can happen fast.

It's most easily explained as that involuntary gasp you take when jumping into any body of water below 70 degrees.

In comparison, the suggested water temperature for the average multi-purpose pool is 84 to 86 degrees, according to the U.S. Water Fitness Association.

“In reality, anything below the temperature of your own body can put you at risk,” Dr. Ryan Stanton, spokesman for the American College of Emergency Physicians, told TODAY. “For a lot of people, that range would be from 55 degrees to 70 degrees Fahrenheit.”

That may not seem cold, but the average body temperature is 98.6 degrees Fahrenheit — so it's an almost 30-degree difference that can literally take your breath away.

“If you take that involuntary gasp for air when you’re under water (after jumping in), you’re going to aspirate, or swallow water, which can lead to panic and can start the drowning process,” said Newman.

This type of shock can also create conditions for a heart attack.

“The body starts pumping adrenaline, which creates changes in the blood vessels in your heart — anyone at risk for heart disease can have a heart attack,” Stanton said. “It can also put people who experience arrhythmia of the heart at risk, and people may not know if they have that condition.”

If you’re able to catch your breath — which is difficult enough to do — the second phase of cold water shock is cold incapacitation — which causes your muscles to eventually stop working.

Cold Water Shock infographic
Cold water shock can happen fast.Angeliki Jackson / TODAY

“In 50-degree water, you might have as little as 10 to 15 minutes of manual dexterity, where you should try to get back on your boat or signal for help in some way. If the water is cold, it’s only a matter of time before you lose control of your arms and legs,” Newman said.

Cold water shock or incapacitation is likely why so many boaters, fishermen, hunters and others drown so quickly, research has shown.

People living in northern regions of the country or in areas with large, rapid flowing rivers are more at risk, said Dr. Peter G. Wernicki, a member of the American Red Cross Scientific Advisory Council.

In 2008, the Coast Guard-funded National Water Safety Congress ran a research project to look into what happens to the body in the first few minutes of exposure to cold water.

As part of the project, Cold Water Boot Camp USA, eight volunteers jumped into 45-degree water. All experienced cold water shock — initial gasp and hyperventilation. After a few minutes, the volunteers couldn't move their arms or legs; they were suffering as cold incapacitation set in.

“Most people think of hypothermia (drop in body temperature) when they think of cold water, but the reality is that if you don’t have a life jacket, you will not live to experience hypothermia — you’ll drown or go unconscious first,” Newman said.

How to stay safe in cold water:

1. Dress for the temperature.

For paddle boarding or surfing, wear a wet suit and always attach to your board.

2. Wear a life jacket.

“A life jacket buys you time — and that’s the key takeaway here,” Newman said. “It buys you time to catch your breath, to rescue yourself and to wait for rescue.”

3. Walk in slowly to better acclimate to cold water temperatures.

Any temperature of water that your body is not accustomed to poses a threat. The surface of a body of water is usually warmer than the temperature of that water a few feet below. Even if you dip your toe in and it feels OK, don't risk quickly submerging your body.

4. If you start shivering or your limbs start to feel stiff, get out of the water immediately.

Even if you're ordinarily a great swimmer, the cold water can immediately debilitate you, warned Stanton.